It doesn't preserve google search options and layout (left menu with video/images/Any time/Hour ago...), so when you are used to standard google from other OSes, you stare at mess mint search makes. Maybe its design that takes too much of top space (around 1/3 on my screen), is too colourful and aligned to left with no padding. I miss integration with google account/plus/picassa (I mean grey bar on top of google pages , not links going through 3 external (redirecting) sites). Btw what is that redirection ( google/cse -> search.linuxmint.com -> some google site ) good for?

And one question, is it true that most of your income comes from custom google search? I don't get how because I don't see any ads or anything.

I write this as I see mint search one of most annoying parts in mint. While I think it got better from what it was first time (its faster imho) there is still space for improvment and that small changes could solve annoyance it generates.

PS: I dont like that only way (I found) to add standard google to search box is to delete your custom one and then add standard.

As has been explained in other threads; the Google custom search engine doesn't allow all standard Google functionality to be used. Also, the possible customization is rather limited.

It is easy to remove and replace with standard Google, but only if you know how to (for any interested, steps are here). I would prefer there was an easy way to revert back to standard Google (for example through Desktop Settings).

It would be better to give more attention to donations, for example on the Welcome Screen.

I would use the mint branded search full time if it had the search options that are in the little menu on google (scholar, translate, etc.), but for now I am changing the default search to plain google.